Heretofore there have existed certain inherent difficulties in gas-driven gas turbine motor which are not analagous to the situations encountered with electrically and mechanically-driven drills. The required lack of resistance to easy rotation by the impinging action and force of pressurized air mandate that there be a minimum of artificial resistance, and that rotation be free and uninhibited substantially. Accordingly, when pressure is applied along a longitudinal axis thereof, in typically the driving of a chuck in a drilling operation, wearing pressure and friction resulting therefrom on the supporting bearings supporting the rotor at each of opposite ends of the rotor space, is excessive, resulting in poor durability and life of the motor. Also, because of the need for maximum effect of the pessurized air, or other driving gas, it is desirable to arrange the housing to achieve maximum drive -- this being a goal not heretofore fully achieved, it has been found in accord with the present invention. From the standpoint of both safety and convenience, it is highly desirable to have some appropriate mechanism for holding steady the chuck-driving shaft and driving rotor thereof during the handling or changing of the chuck, no such device or mechanism existing heretofore.